(CNN) -- The African Union urged the International Criminal Court to postpone cases against sitting leaders as accusations of unfair treatment grow against the war crimes tribunal.
Leaders from the 54-nation body gathered in the Ethiopian capital of Addis Ababa on Saturday to review their relationship with the court based in The Hague, Netherlands.
Kenyan and Sudanese presidents face charges at the court, and African leaders have long accused it of unfair treatment.
'Loud and clear'
"Sitting heads of state and government should not be prosecuted while in office and we have resolved to speak with one voice to make sure that our concerns are heard loud and clear," said Tedros Adhanom Ghebreyesus, the Ethiopian foreign affairs minister.
The trial for Kenyan Deputy President William Ruto is under way while his boss, President Uhuru Kenyatta, is scheduled to appear in court next month.
Both are on trial for alleged crimes against humanity linked to postelection violence six years ago. They deny the charges.
Sudanese President Omar al-Bashir has largely shunned an ICC warrant for his arrest for alleged war crimes.
"We are deeply troubled by the fact that a sitting head of state and his deputy are for the first time being tried in an international court, which infringes on the sovereignty of Kenya and undermines ... the country's reconciliation and reform process," Ghebreyesus said.
Others including Ethiopia and Uganda have joined in, accusing the court of targeting their leaders.
"African countries form the largest constituency of the Rome Statute and I think all of them have expressed issues that they want addressed at one time or another," said Amina Mohamed, the Kenyan minister for foreign affairs. "The summit will present that opportunity."
The International Criminal Court was set up in 2002 to prosecute claims of genocide, crimes against humanity and war crimes. Rights groups say the court is crucial in ending impunity in African politics.
"Some of the most heinous crimes were committed during the conflicts which marked the twentieth century," the ICC said. "Unfortunately, many of these violations of international law have remained unpunished."
Kenya's previous administration reneged on a deal to set up a special tribunal to try suspects in the postelection violence that left more than 1,000 people dead, prompting the international court to step in.
Accusations of double standards
The court has consistently said it is not a substitute for domestic justice systems, and only intervenes if the national judicial system is either unwilling or unable to carry out justice.
But some leaders have accused it of double standards, with the Ethiopian foreign minister saying it is jeopardizing peace efforts.
"The International Criminal Court's way of operating particularly its unfair treatment of Africa and Africans leaves much to be desired," he said.
So far, all cases before the court are against Africans in eight countries, including Ivory Coast , Uganda, Sudan and Mali.
Some of the cases were handed over by their respective African governments, including Ivory Coast; others were referred to the court by the U.N. Security Council.
Rights groups: Court ensures justice for all
Rights groups are urging African leaders to support the court, saying it is crucial in ensuring justice for everyone.
"African countries played an active role at the negotiations to establish the court, and 34 African countries -- a majority of African Union members -- are ICC members," Human Rights Watch said in a statement.
"Any withdrawal from the ICC would send the wrong signal about Africa's commitment to protect and promote human rights and to reject impunity."
The Kenyan parliament voted in September to withdraw from the court's jurisdiction after repeatedly calling on it to drop the cases.
A withdrawal would take a while to implement because it involves steps such as a formal notification to the United Nations.